Heat exchange device



July 10, 1945 P. H. scHoEFuNi-TAL Y 7 2,379,932

HEAT EXCHANGE DEVICE Filed Feb. 18, 1944 2 Sheets-Sh et I1 lN\ IENTOR 5BY 0;, My

ATTORNEYS containing a body of water I? which is evaporated to providethe cooling effect. Toward the rear of this casing is secured a verticalpartition I8 which extend from one side wall to the other and whichterminates a substantial distance above the level of the water II. This.partition I8 provides a relatively large working chamber I in the frontof the casing and an air discharge passage 28 in the rear of the casing.Air is drawn intothe working chamber I9 through an air inlet duct 2| andis discharged from the air discharge passage 28 through an outlet duct22. a

The means for drawing air in through the inlet duct 2|, into the workingchamber I9, and discharging the air around the underside of thepartition I8 and out through the air discharge passage and thedischargeduct 22 comprises a fan 25 mounted upon a vertical fan shaft 25 which isshown as journaled in a bearing 21 in the top of the casing I5 and in abearing 28 mounted on the bottom of the tank I52 This fan shaft isdriven by a, motor 38mounted on the side of the casing i5, through abelt drive 3| or in any other suitable manner. The fan is-shown as beingof thepropeller type and as arranged in a circular open-, ing'35 in ahorizontal baflle or partition 35 which 4 divides the working chamber I9into upper andlower chambers I90. and l9b.

Mounted within the lower chamber l9b is a coolingcoil indicatedgenerally at 38. This cooling coil is shown as comprising a verticalinlet header 4!! of tubular form arranged adjacent the fan shaft 25, asimilar outlet header-42 arranged adjacent the front wall of the casingI5 and a plurality of spiral tubes 43 connecting these headers andpreferably arranged in substantially uniformly spaced relation to oneanother to permit the flow ofair over their external surfaces. This coilassembly can be supported on angle irons 44 which are shown as beingtour in number and secured to the partition I8 and front wall of thecasing I5 in position to support the coil assembly at four places. Theinlet header 'is shown as provided with an inlet pipe 45 to whichthe-pump discharge pipe I4 connects and the outlet header 42 is shown asprovided with an outlet pipe 45 to which th'e pipe I I connects. The airflowing down the chamber I 912 is preferably confined so as to pass inintimate contact with the tubes 43 of the coil 38 and for. this purposethe coil assembly is preferably surrounded by a cylindrical sheet metalshell 48 .which rests upon the angle bars 44 and preferably extendsupwardtubes 43. of the cooling coil 38 so as to keep these tubesconstantly flush'ed with water, the excess water flowing back into thetank "5.

For this purposesa pump is provided which is in the'form of afrusto-conicalshell 50 which can be secured to the fan shaft25 in anysuitable manner and has its lower end of reduced diameter immersedfinthe body of water I! in the tank I5. Adjacent the upperend of this pumpshell 50 is arranged a stationary baflie 5| which surrounds the fanshaft-25 and the .upperfend of the pump shell 58 and is alsooffrusto-conical form. This baflile 5i can be supported on legs or bars 52which are shown as extending radiallyoutward and as secured to thecylindrical shell Means are provided for delivering differentproportions of outside air from the duct 2| and recirculated air fromthe :air discharge passage 20 I5 in any suitable manner and is shown ashaving an external operating lever 59- connected thereto,

as best shown in Fig. 1. This operating lever is shown as connected by alink with the lever 6| ofa damper-motor 52, This damper motor is shownas controlled, through a line 53, from'an immersion thermostat 54 in theoutlet line II although this damper motor 52 can be controlled in any ofthe ways shown in the Olstad and Williams Patents Nos. 2,296,946 and2,321,933.

As shownin Fig. 1, the heat exchanger can also be utilized to remove therust, dirt and smudge laden air from adjacent the cutting operation andto purify this air before being returned into the enclosure. For thispurpose an air filter 55 is shown as mounted across the inlet of the airinlet duct 2I and an air duct 55 is shown as leadin from a pointimmediately above th'e zone of open.

ation of the turret lathe 10 to the filter. 55. As a result the dust,dirt or smudge laden air developed during the cutting operation is drawnby the heat exchanger through the duct 55 and filter temperature at thestart of an operation and also to prevent it from falling below thisproper temperature at any time. For this purpose an electric heater 5!is shown as mounted in the wall of the tank I5 and as having its heatingsurface immersed in the body of spray water I! in this tank. Thisimmersion heater is shown as being under control of another. immersionthermostat 68 in th'e outlet line I I through acontrol line 55, thethermostat 58 being set to close the circuit through the immersionheater- 5'! whenever the temperature of the fluid passing through lineII drops below the proper operating temperature.

However, the heat could be applied by injecting steam into the spraywater, or by steam or other heating coils, and the immersion heater 51could be under control of th'e thermostat 54 or the thermostat "could bearranged in the body I I of spray water, the air stream, or the fluidline I4,

reference being made to the Olstad and Williams Patents Nos. 2,296,946and 2,321,933 for such 4 modifications ofthe control.

In the operation of the form of the invention shown in Figs. 1-3, thecutting fluid or compound collects in the pan I2 of the machine 'tooloi" through the various spiral tubes 43 of the coil 38 1 and passes intothe outlet header 42 and through its outlet pipe 46 into the pipe IIfrom which the cutting fluid is discharged against the piece of workbeing operated upon in the machine tool Hi; Smudge laden air is at thesame time being drawn by the fan 25 from the zone of operation ofthemachine tool lll'into the duct 88 and through the air filter 65 whichremoves the dirt, dust and smudge and purifies the air. From this filterthe air is drawn by the fan 25, through the air inlet duct 2| into theupper chamber l9a, the fan 25 forcing this air downwardly around thetubes 43 of the cooling coil 38 and around the underside of the verticalpartition l8 into the air discharge passage 20. From the upper end ofthis air discharge passage the all is discharged back into the enclosurethrough the air dis charge duct 22. At the same time the frustoconicalpump shell 50 is rotating with this shaft 26 and since this pumpshell 50is of upwardly enlarging tapering form, water is drawn from the body Hin the tank I 6 up through this shell and discharged horizontallyoutward from its upper end against the frusto-conical stationary baffle5|, this water being thereby deflected downwardly upon the tubes 43 ofthe cooling coil 38 so as to flush these tubes in a wetted condition.This water evaporates on these tubes, the tubes 43 tending to assume thewet bulb temperature of the air forced downwardly around these tubes bythe fan 25. The fluid passing through the tubes 43 of the cooling coilis thereby subjected to evaporative cooling before being returned to themachine tool.

Under heavy load conditions, where the maximum cooling effect upon thefluid under treatment is desired, the damper 54 is held in the verticalcondition shown in which the air inlet and outlet ducts aresubstantially segregated from each other so that only fresh air ispassed through the apparatus. With a decrease in the cooling load uponthe apparatus, the falling temperature of the leaving fluid undertreatment actuates the thermostat 64 and the damper motor 6,2 to movethe damper 54 from the full line position shown in Fig. 2 toward thedotted line position there shown. When this occurs recirculated air fromthe air discharge passage 20 is drawn, together with fresh air from theair intake duct 2|, into the chamber No by the fan and passed throughthe cooling coil 38. Since this recirculated air withdrawn from the airdischarge passage 28 has been heated by pass ing the bani: of tubes 43and also is substantially saturated with the moisture evaporated inpassing through these flooded coils, it will be seen that the mixedfresh and recirculated air now supplied to the chamber l9a has a higherwet bulb temperature and hence the evaporative cooling effect of thewater and air passing over the bank of coils or tubes 43 is reduced. Itwill therefore be seen that the immersion thermostat 84 in the fluidlinell maintains a substantially constant temperature of the fluid bythe operation of the damper 54, opening this damper when the temperatureof the fluid falls below that desired and closing this damper whengreater.

cooling is required.

At the start of an operation, or if at any time the temperature of thecutting oil or other fluid being treated drops below the propertemperature, the immersion thermostat 88 in the fluid.

line H acts through its control line 69 to energize the immersion heater81. This heats the body of spray water I! and since this s ray. water isbeing sprayed over the coils 43, this spray waform of the inventionshown in Figs. 1-3 the bottom part of the casing is formed to provide atank containing a body ofwater 16 which is evaporated to provide thecooling effect. To-

ward the rear wall ll of the casingis secured a vertical partition whichextends from one side wall 12 to the other and which terminates asubstantial distance above the level of the, body of water 18. Thispartition 80 provide a relatively large working chamber 8| and an airpassage 82 in the rear of the casing. The upper end of the air passage82 is divided by a vertical central partition 84 into an air dischargeduct, 85 and an air inlet duct 86. The air discharge duct 85communicates through an opening 98 with the upper end of the workingchamber 8i and also with the air passage 82, the latter communicationbeing under control of a damper as hereinafter described.

The means for drawing air in through the air inlet duct 88, into theworking chamber 8! and discharging the air around the underside of thepartition 88 and out through the air passage82 and air discharge duct 85comprises a fan 90 mounted on a vertical fan shaft 92 and which alsoforms the shaft for a motor 93 mounted on the top wall 15 of the.casing. The fan is shown as being of the centrifugal type and asarranged immediately above an opening 95 in a horizontal partition 96which divides the working chamber 8| into upper and lower chambers Maand MD. This opening 95 forms the eye of the fan.

Mounted within the lower chamber 8| b is a cooling coil indicatedgenerally at 98, This cooling coil is of substantially the same form aswith the form of the invention shown in Figs. 1-3, having a fluid inlet99 leading to a vertical inlet header lllfl'of tubular form arrangedadjacent the fan shaft 92,'and having a similar outlet header (notshown) from which fluid to be cooled is discharged through an outletpipe I04 connecting-with an outlet line I05. These headers are connectedby a plurality of spiral tubes llll and preferably arranged insubstantially uniformly spaced relation to one another to permit theflow of air over their external surfaces. As with the form of theinvention shown in Figs. 1-3, this coil assembly can be supportedonangle irons I02 secured to the casing 10 and partition 89 and is shownas surrounded by a cylindrical sheet metal.

by the evaporation of water and for this purpose water is lifted fromthe body of water 16 in the bottom of the casing and discharged over thetubes ll of the cooling coil 98 so as to keep these tubes constantlyflushed with water, the

excess water flowing back into the body of water 16.

For this purpose a pump is provided which is in the form of afrusto-conical shell IIO secured in any suitable'manner to the lower endof the fan shaft 92 and having its lower end of reduced diameterimmersed in the body of water H5. The upper end of this frusto-conicalshell or sleeve is arranged above the level of the cooling coil 98 andthe water drawn up the inside of the revolving shell IIO 'by centrifugalforce is there- 'fore spread over the cooling coil 08 so as to keep itwet.

Means are provided for delivering different proportions of outside airfrom the inlet duct 86 and recirculated air from the air discharge pas;sage 84 into the lower chamber 8Ib-, the flow of air being in reverse tothat shown in Figs. 1-3. For this purpose a single damper shaft II5extends horizontally across the air passage 82 parallel with thepartition 80 and also extends through the lower part of the partition 84in this passage 82. Within the air inlet passage 86 a damper H6 ismounted on this damper shaft H5 and within the air discharge passage 85a damper III is mounted on this shaft. The dampers II6 and II! arearranged to work in inverse relation to each other andhence are set at a90 angle to each other. The damper shaft is actuated by l a lever armII8 which can be actuated by a damper motor (not shown) in the samemanner as with the damper motor 62 in the form of the invention shown inFigs. 1--3.

In order to prevent entrained water from being drawn up into the fan 90with the stream of air drawn into the fan, an eliminator I of anysuitable form is preferably arranged in the upper part of the chamber8Ib and through which the air is required to,pass. This eliminator isshown as made of V-shaped plates whereby the air is 92 is rotating andsince this pump shell is of upwardly enlarging tapering form, water isdrawn from the body 16 in the bottom of the casing an is dischargedhorizontally outward from'its upper end over the tubes IOI of the coil98 soas to constantly flush these tubes and -maintain the lower end ofthe chamber 8Ib. The fluid to be cooled passing through the tubes IOI ofthe cooling coil is to be subjected to evaporative whipped back andforth so that any entrained water is caught by the plates and returnedto the bottom of the casing.

The control for the form of the invention shown in Figs. 4 and 5 can bethe same as that described with reference to Figs. 1-3. Thus the dampersH6 and Ill can be actuated in response to temperature changes in thespray water, air, or fluid being treated and an electric heater I25 isshown as immersed in the body 16 of spray water in the tank It and ascontrolled through a line I26 from an immersion thermostat I21 in thefluid line I05. This heater and thermostat acts in the same manner asthe immersion heater 61 and thermostat 68 in Figs. 1-3 to prevent thetemperature of the fluid under treatment from ever dropping below apredetermined minimum and thereby insures that the fluid is always heldin a closely controlled temperature range.

In the operation of the form of the invention shown in Figs. 4 and 5,the fluid to be cooled is passed from the inlet pipe 99 through thetubes IOI of'the coil'98 and is discharged through the outlet lineI04'and pipe I05. Fresh or outside air is drawn in through the inletduct or passage 86 into the air passage 82, around the underside of thevertical partition 80'up through the cylindrical shell I03 in intimatecontact with the tubes- IOI of the cooling coil 98, past the eliminatorI20 and into the inlet or eye 95 of the fan 90. This fan discharges theair into the chamber am from which it passes through the opening 08 intothe air discharge duct 85;

At the same time the frusto-conical pump shell IIO secured to the lowerend of the fan shaft (ill ' severe and constant use without requiringrepair. 1

cooling.

Under heavy load conditions, where maximum cooling effect upon thecutting fluid is desired, the fresh air damper H6 is opened and therecirculated air damper III is closed, the air thereby flowing throughthe path which was described. With a decrease in load upon theapparatus, the damper shaft II5 can be set, either manually orautomatically as by the damper motor 62 shown in Fig. 1, so as to movethefresh air damper IIB toward a closed position and so as to move therecirculated air damper III toward its open position. this position ofthese dampers being shown in Fig. 4. When this ocdrawn, together withfresh air from the inlet duct 86,- into the air passage 82 and is passedthrough the cooling coil 98. Since this recirculated air withdrawn fromthe upper chamber 0 la, has been heated by passing the bank of tubes IOIand also is substantially saturated with the moisture evaporated inpassing around these flooded tubes, it will be seen that the mixed freshand recirculated air now supplied to the lower end of the chamber BIbhas a higher wet bulb temperature and hence that the evaporative coolingeffect of the water and air passing over the bank of coils or tubes INis reduced. It will therefore be seen that the adjustment of the dampersH6 and III determines the effective cooling performed by the apparatusand that this can be held within very close limits.

At the start of an operation or if at any time the temperature of thefluid under treatment drops below the proper working temperature, theimmersion thermostat I21, through its control line I26, energizes theelectric immersion heater I25 thereby to heat the body of spray waterI6. Since this spray water is being sprayed over the coils IOI, it willbe seen that the temperature of the liquid being treated is therebyautomatically restored to its proper operating minimum.

From the foregoing it will be seen that the present invention provides avery-simple, inexpensive and rugged heat exchanger of the evaporativetype which is particularly adapted for relatively small units. It willfurther be seen that the evaporator can be used both to cool the fluidsupplied to a part being processed for the purpose of cooling the partand also for-purifying the dirt, dust and smudge laden air resultingfrom such processing. It will further be seen that the apparatus is freefrom operating .difllculties and will stand up under conditions of Weclaim as our invention:

1. A heat exchange device for cooling a stream of fluid, comprising anenclosing casing having top, bottom and side walls, a vertical partitionextending across the interior of said casing and extending downwardlyshort of the bottom r thereof, said vertical partition providing aworking chamber on one side and an air passage on its opposite side, anair duct connected with the upper end of said air passage, an air ductconnected with the upper part of said working chamber, a fan arranged toforce a stream of air through said air ducts, air passage, workingchamber and under said partition, a cooling coil arranged in saidworking chamber and-in the stream of air passing therethrough, means fordischarging and distributing water over said cool-- ing coil to wet theexterior of said cooling coil and to evaporate and absorb heattherefrom, and means for conducting the said stream of fluid to becooled through said cooling coil.

2. A heat exchange device for cooling a stream of fluid, comprising anenclosing casing having top, bottom and side walls, a vertical partitionextending across the interior of said casing and extending downwardlyshort of the bottomthereof, said vertical partition providing a workingY chamber on one side and an air passage on its. opposite side, on airduct connected with the upper end of said air passage, an air duct con-1,nected with the upper part of said working chamher, a horizontalpartition arranged across the upper part of said working chamber andspaced from the top of said casing, said horizontaiparti time beingprovidedwith an opening forming the eye of a fan, a fan wheel rotatingabout a vertical axis concentric with said opening and drawing airtherethrough to force a stream of air through said air ducts, airpassage, working chamber and under said partition, a cooling coilarranged in said working chamber below said horizontal partition and inthe stream of air passing. therethrough, means for discharging, anddistributing water over said cooling coil to wet the exterior of saidcooling coil and to evaporate and absorb heat therefrom, and means forcon i ducting the said stream .of fluid to be cooled through saidcooling coil.

3. A heat exchange device for cooling a stream oi iiuid, comprising anenclosing easing, a vertieal partition extending across the interior oisaid-casing and extending downwardly short of the bottom thereof, saidvertical partition providing a working chamber on one side and an airpassage on its opposite side, an air duct con heated with said airpassage, an air duct connected with the upper part of said workingchamber, a fan shaft extending vertically through said working chamber,means for retoting said fan shaft, a fan wheel fast to said fan shaftand arranged in the upper part oi said working chamber, and forcing astreamwi air through said air fducts, air passage, working chamber andunder said partition, a cooling coil arranged in the lower part oi saidworking chemher around said fan shaft and in the stream of air passingthrough said working chamber, said casing being formed to provide atanlr for rctaining a body of water at its bottom; means carried by saidfan shaft for elevating water from said body and discharging anddistributing said all; passage n its opposite side, an air ductconnected with said air passage, an air duct connected with the upperpart of said working chamber, a fanshaft extending vertically throughsaid working chamber, means for rotating said fan shaft, a fan wheeliast'to said fan shaft and arranged in the upper part of said workingchaniher and forcing a stream of air through said air ducts, airpassage, working chamber and under said partition, a cooling coil.arranged in the lower part of said working chamber around said fan shaftand in the stream of air passing through said working chamber, saidcasing being formed to provide a tank for retaining a body of water atits bottom,-a frusto-conical sleeve fast to the lower end or said fanshaft and having its lower reduced end immersed in said body of waterthereby. to elevate said water and discharge and distribute said waterover said cooling coil to,

wet the exterior of said cooling coil and to evaporate and absorb heattherefrom, and means for conducting the said stream of fluid to becooled through said cooling coil.

-5. A heat'exchauge device for cooling a stream of fluid, comprising anenclosing casing, a vertical partition extending across the interior oisaid casing and extending downwardly short oi the bottom thereof, saidvertical partition providing a working chamber on one side and an airpassage on its oppositeside, an air duct connected with said airpassage, an air duct connected with the upper part'of said workingchamber, a'horizontal partition arranged across the upper part of saidworking chamber and spaced from the top of said casing, said horizontalpartition being provided with an opening forming the eye of a fan, a fanshaft extending vertically through said working chamber andsaid-opening,

means for rotating said fan shaft, a fan wheel fast to said shaftadjacent said opening and drawing air therethrough to force a stream. ofair through said air ducts, air passage, working chamber and undersaid-vertical partition, a'cooling coil arranged in saidworking chamberbelow said horizontal partition and in the stream of air passingtherethrough, said casing being formed to provide a tanir for retaininga body of water in its bottom, means carried bysaid fan shaft forelevating said water and discharging it between said horizontalpartition and said cooling coil to be distributed over said cooling coilto evaporate and absorb heat therefrom, and means for conducting the'stream of fluid to be cooled through said cooling coil. 1

6. A heat exchange device for adjustabiy coolin: a stream .of fluid,comprising an enclosing casing, partition means-within said casing andforming an air inlet passage, a working chamber and an air outletpassage, is fan in said working chamber arranged to force a stream oiair successively through said air inlet passage, working chamber and airoutlet passage, a cooling coil arranged in said working chamber and inthe stream of air passing therethrough, means ifor discharginganddistributing water over said cool? ing-coil to wet the exterior ofsaid cooling coil and to evaporate and absorb heat therefrom, means forconducting the said stream of fluid to be cooled through said coolingcoil, and means ior adjusting the temperature of the leaving fluid,

comprising an opening in'said partition between 1 said air inlet passageand said air outlet passage and through which ,air canrecirculate fromsaid air outlet passage to said air inlet passage, a

damper shalt extending across said opening." damper means i'ast to said.damper shaft and rezulating the proportion of air discharged from saidair discharge passage and through said 'recircu 7. A heat exchangedevice for adjustably cooling astream of fluid, comprising an enclosingcasing. a vertical partition across the interior of said casing andextending downwardly short of the bottom thereof, said verticalpartition providing a working chamber on one side and an air passage onits opposite side, an air inlet duct connected-with the upper end ofsaid air passage, an air outlet duct connected with the upper part ofsaidworking chamber immediately adjacent said partition, a fan arrangedto move a stream of air from said air inlet duct downwardly through saidair passagaaround the underside of said partition, upwardly through saidworking chamber and out through said air outlet duct, a

cooling coil arranged in said working chamber and in the stream of airpassing therethrough,

means for discharging and distributing water over said cooling coil towet the exterior of said cooling be cooled through said cooling coil,and means for adjusting the temperature of the leaving fluid,

comprising an opening in said partition between ing a stream of fluid,comprising an enclosing casing, avertical partition across the interiorof said casing and extending downwardly short of the bottom thereof,said vertical partition providing a working chamber on one side and anair passage on its opposite side, a vertical partition extendingtransversely across the upper part of coil and to evaporate and absorbheat therefrom, means for conducting the said stream of fluid to saidairpassage and providing an air inlet duct,

1 on oneiside and an ,air'outlet duct on the other side, saidflrstvertical partition being providingflow of air from said air inletduct, into said air chamber having an air inlet and shah outlet, is. fanarranged to force a stream of air from said inlet, through said chamberand out through said outlet, a cooling coil arranged in the stream ofair passing through said chamber, means discharging and distributing astream of water over said cooling coil to wet the exterior of saidcooling coil and to evaporate and absorb'heat therefrom, meansconducting said stream of fluid to be cooled through said cooling coilthereby to cool said stream of fluid before said application to saidpart, and means conducting said dirt, dust which requires theapplication of a stream of. fluid on the part being operated onresulting T in the generation of .dirt, dust or smudge in the airsurrounding the zone of operation of said machine tool on said part,apparatus for cooling said stream of fluid and for purifying the dirt,dust or smudge laden air resulting from said operation, comprising'meansforming a chamber having an air inlet and an air outlet, a fan arrangedto force a stream of air from said inlet, through said chamber and outthrough said outlet, a cooling coil arranged in the stream of airpassing through said chamber, means discharging-and distributing astream of water over said cooling coil to wet the exterior of saidcooling coil and to evaporate and absorb heat thereair inlet.

11. In combination with a machine tool which changes the form of a partbeing operated on.

and which requires the application of a stream of fluid on the partbeing operated on resulting in the generation of dirt, dust'or smudgeinthe air surrounding the zone of operation of said machine tool on saidpart, means forming a passage, a second damper fast to said damper shaftand at an angle toisaid first damper and arranged to restrict the flowof air from said air outlet duct into said air passage, a fan arrangedto move a stream of air from said air inlet duct, downwardly throughsaid air passage, around the underside of said partition, upwardlythrough said working chamber and out through said air outlet duct, acooling coil arranged in said working chamber and in the stream of airpassing therethrough, means for discharging and distr-ibchamber havingan air inlet and an air outlet a ,fan arranged to force a stream of airfrom said inlet, through said chamber and out through said outlet, acooling coil arranged in the stream of air passing through said chamber,means discharging and distributing a stream of water over,

said cooling coil to wet the exterior of said cooling coil and toevaporate and absorb heat therezone of operation is drawn into saidchamberby uting water over said cooling coil to wet the exterior' ofsaid cooling coil and to evaporate and I absorb heat therefrom, meansforconducting the 9; In combination with a machine tool which W changesthe form of a part being operated on and which requires the applicationof a stream of fluid on the part being operated on resulting in thegeneration of dirt, dust-orsmudge in the air surrounding the zone ofoperation of said machine tool on said part, means forming a said fan,and an air filter in the path of the air so drawn through said ductthereby to purify the dirt, dust or smudge laden air resulting from saidoperation.

12. In combination with a machine, tool which changes the form of a partbeing operated on and chamber having an air inlet and an air outlet, av

fan arranged to force astream of air from said inlet, through saidchamber and out through said outlet, a cooling coil arranged in thestream of air passing through said chamber, means discharging anddistributing a stream of water over said cooling coil to wet theexterior of said cooling coil and to evaporate and absorb heattherefrom, means at the bottom of said chamber collecting said spraywater, means recirculating said collected spray water through saiddischarging and distributing means, means conducting said stream offluid to be cooled through said cooling coil thereby to cool said streamof fluid before application to said part, a duct connected with said airinlet, a hood connected with the other end of said duct and arrangedover said zone of operation whereby the air from said zone oi! operationis drawn through said chamber by said fan, and an air filter in the pathof the air so drawn through said duct thereby to purify the dirt, dustor smudge laden air resulting from said operation. a

13. In combination with a machine tool which changes the form of a partbeing operated on and which requires the application of a stream oi.fluid on the part being operated on resulting in the generation of dirt,dust or smudge in the air surrounding the zone of operation of saidmachine tool on said part, means forming a chamber havingan air inletand an air outlet, a

fan arranged to force a stream oi! air from said inlet, through saidchamber and out through said outlet, a cooling coil arranged in thestream of air passing throughsai'd chamber, means dischargingand-distributing a stream of water over said cooling coil to wet theexterior of said cooling coil and to evaporate and absorb heattherefrom, means conducting said stream of fluid to be cooled throughsaid cooling coil thereby to cool said stream of fluid before saidapplication to said part, said streams of air and water normally beingheated through heat derived from said stream of fluid passing throughsaid cooling coil, air recirculation means for conducting a part of thestream of air leaving said chamber back to said air inlet,thermostatmeans responsive to the temperature of one of said streams toadjust the amount of air so conducted back by said air recirculationmeansto maintain the temperature of said stream of fluid in a selectedtemperature range, and means conducting said dirt, dust or smudge ladenair from said zone of operation to said air inlet thereby to purify thedirt, dust or smudge laden air resulting fromsaid operation.

PAUL H. SCHOEPFLIN.

CHARLES N. DEVERALL. RbBERT c. s'ru'rz.

